Which of the following characteristic features always holds true for the corresponding group of animals?
- Cartilaginous endoskeleton - Chondrichthyes
- Viviparous - All mammals
- Possess a mouth with an upper and a lower jaw - Chordata
- 3 – chambered heart with one incompletely divided ventricle - Reptilia
Solution
Reptillia has an order crocodilian which shows 4 chambered heart.
In mammals, prototheria group shows oviparity while metatheria and eutherian show viviparity.
Chordates can be gnathostomata (jawed organism) and agnatha (without jaws).
Only cartilaginous fishes (chondrichthyes) show cartilaginous endoskeleton without any exception.
Asked in: NEET 2016 (Phase 1)